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1/41. 2. 3. 4. 5. 6. 1. 2. 3. 4. 5. 6. 7. 8. Automate Circuits Analyses with the NI LabVIEW Multisim API ToolkitPublish Date: Oct 07, 2013OverviewThe NI LabVIEW Multisim API Toolkit has been developed for the LabVIEW environment and provides access to more than 120 functions to automate the simulation of a Multisim circuit fromLabVIEW. This toolkit is an innovative new connection between the worlds of design and graphical programming. You can for automate simulations easily from a graphical programming language,to: Access simulated measurements within the LabVIEW environment for further, domain specific analysis Correlate simulated and real measurements in a single LabVIEW environment Use simulated measurements as a design under test (DUT), in order to build test/validate cases earlier in the design flowTable of ContentsIntroductionWhat is the LabVIEW Multisim API Toolkit?How to Install the LabVIEW Multisim API ToolkitExample 1: Efficiency Calculation of a Buck ConverterExample 2: Automating a Simulation of a Signal Conditioning Circuit with Acquired Heart-Beat SignalAdditional Resources1. IntroductionMultisim allows engineers to use simulation to optimize the performance of designs earlier in the design flow and ensure circuits meet specifications with fewer prototype iterations. The LabVIEWMultisim API toolkit added in Multisim 13.0 enables designers of analog and mixed-mode circuits to easily create graphical program in LabVIEW that rapidly perform or automate critical designtasks which is impossible in other simulation tools. Some of the critical types of analyses that are available include:Evaluating circuit performance with non-ideal signals from real measurementsVisualizing outputs of circuits in custom graphs and interfacesAutomating and iterating through different design scenarios with LabVIEW2. What is the LabVIEW Multisim API Toolkit?Multisim natively provides an Application Programming Interface (API) that allows for the automation of circuit simulation and analyses through a COM interface that designers can use toprogrammatically control.The LabVIEW Multisim API Toolkit is a collection of VIs that makes the Multisim API ready-to-use for LabVIEW users. With this API toolkit users can take advantage of over 120 ready-to-useLabVIEW Virtual Instruments (VIs) to:Establish a connection to Multisim, check the connection status, disconnect from Multisim, query the application location and version.Manage Multisim files (open, create and save files, as well as query file information).Configure inputs and outputs, as well as also set data for inputs or get data from outputs.Control and check the state of the simulation (DC, AC, or Transient). Execute analyses and use the SPICE command line.Configure component values, switch models, change circuit parameters, and replace variants of a Multisim circuit.Perform different utility functions. Check for error messages, get a circuit image or generate reports.3. How to Install the LabVIEW Multisim API ToolkitThe LabVIEW Multisim API Toolkit is installed automatically with Multisim 13 4. Example 1: Efficiency Calculation of a Buck ConverterThis example uses theLabVIEW Multisim API Toolkit to iterate through multiple critical values in a circuit in an automated fashion to assist us in calculating efficiency. Without a toolkit such as thisone in LabVIEW an individual would try to optimize efficiency by manually changing values in a circuit and recording the simulated value in each. This is time consuming and error-prone.Our goal for this example will therefore be to set the switching frequency of parameters on a buck converter based on NXP components and then perform a sweep across several switchingfrequency, values. For each step a transient analysis is run and the efficiency of the circuit is automatically calculated. This can all then be plotted and the best switching frequency will beFsw,observed through this process.2/4Using the circuit parameters (click to learn more about circuit parameters) and toolkit we can step through the development of this test.hereAll the example files are attached to this document in the folder called apidemo.zipOpen the file in LabVIEW 2013Circuit Parameters.viGo to the block diagram and see the new VIs for the Multisim connectivity. They are under ConnectivityMultisim Notice how from LabVIEW there are now ready to use VIs for establishing a Multisim connection, running simulation files, configuring circuits, and read/write IOs.On the block diagram there are available explanations on what each of the VIs accomplishes. Open the Multisim circuit that this VI is supposed to control and notice the DC-DC buck circuit converting 10V to 3.1V (BuckConverter_API.ms13).Run a quick interactive simulation by pressing the play button to evaluate the circuit operation. The probes should be showing the expected values. 3/4 Go to the LabVIEW front panel and run the VILabVIEW is now controlling Multisim and iterating over multiple values of the switching frequency and creating a plot of the circuit efficiencyBy using this approach we can clearly see the various efficiency values of our circuit. The best option can be chosen and we have been able to automate what has traditionally been a complex anderror-heavy process 5. Example 2: Automating a Simulation of a Signal Conditioning Circuit with Acquired Heart-Beat SignalIn this example a signal conditioning circuit is designed in Multisim to filter acquired heartbeat signals for the development of a biomedical device application.The circuit is a single stage active filter using operational amplifiers from Texas Instruments. While the heart beat signals are real-world signals that could be acquired using a sensor device orsimulated using the LabVIEW Biomedical Toolkit.All the design files of this example are in the attached file sigcond.rar 4/4 As you can see the transient simulation in Multisim could be used to evaluate whether the chosen op-amp will provide the desired filtering response or not for this low-voltage signal. However, forthe purpose of this design, the LabVIEW Multisim API Toolkit is leveraged to automate multiple simulation runs that:Iterate over a various selection of op-amp to determine which op-amp provide better conditioningIterate over various input heart-beat signals with various noise levelsCalculate the transient responses for each op-amp versus multiple input noise levelsPerform advanced signal processing tasks to calculate critical parameters such as the Signal to Noise Ratio (SNR)The application below is written in LabVIEW. You can simply download and run under the project .main.vi Heart Beat Signal Conditioning.lvproj As you can see using this automation code multiple output plots for different op-amps and input signals have been very easily created. Also the table on top of the graph indicates the differentcorresponding SNR values. Without the automation of LabVIEW this toolkit provides, such calculation would a separate simulation run for each case which is a lengthy process. 6. Additional ResourcesDownload MultisimLearn about more Multisim circuit design applications 1/71. 2. 3. 4. 5. 6. 7. 1. 2. 3. Flight and Camera Electronics for a Satellite System - A NI Multisim National Lab ApplicationPublish Date: Oct 06, 2013Table of ContentsProductsThe Design ApplicationThe ChallengeThe SolutionImproving the Productivity Platform with the LabVIEW Multisim API ToolkitAutomated Validation using Multisim and LabVIEWAutomating Validation1. ProductsNI Multisim, NI LabVIEW and PXIOne of the great hurdles in the modern design flow is the inability to effectively prototype a design and compare its behavioral measurements to the initial design specifications. This barrier toeffective design is detrimental to engineers who want to be able to quickly verify and validate their prototypes with simulated behavior. The integration between the Multisim capture and simulation environment, and the LabVIEW graphical programming language, provides a streamlined and integrated path for measurements toflow through the design flow. This improves the productivity of engineers. 2. The Design ApplicationThis real-world application, involved the design of flight and optical electronics for satellite systems. Due to the advanced nature of this design, design accuracy was paramount, and as such thesimulation of this application needed to mirror real-world elements as closely as possible. 3. The ChallengeThis R&D laboratory was responsible for the rapid design and validation of flight and camera electronics for a satellite system. Since this system would not only be airborne, but also orbitingvarious objects in space, it was important that initial design specifications be met for every element of the satellite system. Due to the nature of the environment in which the satellite would beoperating (space), advanced analysis was necessary to validate the performance of the design.The engineers needed to be able to quickly verify their design decisions through simulation for the approval of management, and quickly transition to prototyping. Since the application representedmultiple areas of domain intelligence (electronics, vision, aerospace etc) it was important that the design platform be flexible and easy-to-use. Finally, to ensure success in benchmarking theprototype behavior, rapid and easy correlation of simulated and real measurements was required. 4. The SolutionIt is first important to understand the overall design approach that occurred on this satellite design. There were three stages to the design flow:The design needed to be presented to management and receive approvalDesign needed to be quickly simulated and definedCompleted design is handed to a layout team, to build a schematic and layout with the enterprise tools Design Approval: MultisimMultisim was used for the initial design proposal. By quickly building the schematic and simulating its behavior, the engineers were able to provide management with immediate visual verification ofdesign decisions. Multisim utilizes SPICE simulation to emulate the behavior of circuit devices such as transistors, diodes, operational amplifiers and passive components. Utilizing specificanalyses and interactive simulation, the engineer can visualize emulated design behavior prior to physically prototyping the board. Thereby engineers, and in this case, also management, cangraphically judge the behavior of a design, respond to limitations, and improve performance.With an initial design implemented to showcase the behavior of the flight electronics, management was able to approve the scope of the project on the strength of this simulated behavior.The design now focussed on improving design behavior. There were multiple factors to take into account in evaluating circuit performance:Analyze the performance in extraterrestrial environments (i.e. space) at set temperatures, ability to handle dust etcVerify overall operation of flight electronicsValidate the capture and processing of optical information from camera data Effective Design with a Validation PlatformA key challenge for engineers is the ability to effectively validate the behavior of prototype circuits, and compare them to design specifications. Using an integrated platform, through which the testenvironment is able to view simulated data, it is immediately possible to compare, and benchmark, real measurements to design specifications.The laboratory, upon the definition of this project, had stated that their test and validation needs included:Rapid acquisition of design performance2/7Rapid acquisition of design performanceComparison of real and simulated measurements to benchmark prototype performanceEasy setup of test equipment for validation and verificationThe LabVIEW graphical programming is suited to the development of applications that connect to measurement acquisition hardware. In LabVIEW, applications can be programmed that willacquire, analyze and present real data on the computer screen.The unique integration between LabVIEW and Multisim, means that simulated data can be saved to a native file format, that can be transferred and read within LabVIEW. Multisim and LabVIEWwere therefore able to communicate via the LabVIEW Measurement File format (LVM), which is an ASCII based file containing measurements corresponding to time-base. Simulated and real measurements can be plot upon the same graph axes, to analyze any difference. With this highly graphical approach any deviations of the prototype from the expectations setby simulation can be identified, further analyzed and resolved. The test platform was built using LabVIEW SignalExpress and PXI. LabVIEW SignalExpress is a completely graphical environment, with pre-configured measurement steps which require noprogramming. With this version of LabVIEW, the engineers were able to quickly place graphical into an ordered list, to configure their operation. Each is a graphical interface to anstepsstepinstrument, or analysis within SignalExpress. For example, below we see a configuration step for a digitizer to acquire measurements from physical hardware. 3/71. 2. 3. Validation PlatformThe hardware setup which interrogated the physical prototype was based upon the PXI (PCI eXtensions for instrumentation) platform. PXI is an open, PC-based platform for test andmeasurement. As a part of this platform, the engineer can connect modular instruments (such as digitizers, arbitrary waveform generators, DMMs etc) into PCI slots in the PXI chassis. Thisprovides a cost-effective desktop based measurement system (with a small footprint). LabVIEW SignalExpress allows for easy, graphical based setup and configuration of these measurementmodules.Below we see the PXI platform utilized for this application.Instruments in PXIDigitizer/Scope: NI 5114 250 MS/s scopeSource/Waveform Generator: NI 5412 200 MS/s Arbitrary WaveformGeneratorDigital I/O: NI 6534 Digital Waveform I/O The final design prototype was connected to the PXI hardware. LabVIEW SignalExpress was used to acquire these real measurements. Simulated data from Multisim was transferred to LabVIEWSignalExpress in the LVM format.With real measurements being acquired through LabVIEW SignalExpress, and with the transfer of simulated data coordinated, we can correlate both sets of data. By viewing the differencesbetween the data, the process of benchmarking and validating performance is easily done. Design CompletionHaving effectively correlated the two sets of data, the prototype performance was verified as meeting design specifications. Due to the integrated approach, the design flow for the engineer was4/7Having effectively correlated the two sets of data, the prototype performance was verified as meeting design specifications. Due to the integrated approach, the design flow for the engineer wasimproved throughout, from gaining manager approval, to validating the prototype.The schematics to the flight and optical systems were at this point printed out, and handed to the board layout group at the National Lab. Utilizing the final layout software, the design wasfabricated using the enterprise tools. 5. Improving the Productivity Platform with the LabVIEW Multisim API ToolkitThe approach above, recounts the method utilized by a laboratory to validate the behavior of electronics with Multisim, LabVIEW SignalExpress and PXI. With recent developments in the Multisimsoftware, validation has been completely integrated into LabVIEW, to remove the need of file transfer, and to be able to completely automate simulation.The allows any COM-aware programming language to connect to Multisim simulation, and leverage those measurements within its environment. As such LabVIEW Multisim Automation APILabVIEW, can connect to this automation feature, and immediately acquire these simulation results, in a fashion similar to which it acquires real data. In a single LabVIEW application, theengineers from the National Lab discussed above, can now completely automate the acquisition and analysis of simulated and real data.The Multisim Automation API is wrapped with LabVIEW VIs to make it easy to use the highly graphical environment of LabVIEW to build an automated validation application. LabVIEW Multisim API ToolkitThe LabVIEW Multisim API Toolkit is a set of wrappers for the Multisim Automation API. All the various functions such as opening, closing, and viewing a circuit, as well as running, pausing andstopping simulation have been organized into VIs. This means that rather than having to access Active-X controls, standard LabVIEW programming practices can be utilized.To view more data about the LabVIEW Multisim API Toolkit, refer to this tutorial.6. Automated Validation using Multisim and LabVIEWTo showcase this integration, and the ability to automate the validation of a design, we can investigate the attached proof of concept using Multisim, LabVIEW and PXI. Schematic Capture and SimulationSimilar to the design approach above, our goal is to simulate a circuit, fabricate a prototype, and then compare both sets of measurements.The schematic of this design, shown below, defines a 8 kHz bandpass filter. The performance of the validate circuit is shown in the Multisim AC analysis below. As we can see, based upon the bandpass filter we have designed, we indeed have a pass band at 8 kHz asspecified.5/7 PrototypeSince the design has met specifications based upon the simulated output, we are ready to layout and route the board. For this particular design, the bandpass filter is a part of a group ofdemonstration circuits, all of which reside upon a single PCB. Hardware SetupWith the physical prototype built, we connect it to a PXI chassis as shown below, with two BNC connectors connecting the digitizer (oscilloscope) to the input and output of the prototype. Anarbitrary waveform generator is connected to the input of the bandpass filter. 7. Automating ValidationAs discussed previously, this is normally the stage at which simulated measurements would be transferred to the LabVIEW or LabVIEW SignalExpress test environment, as with the aboveapproach. However with the advent of automated simulation, we can instead create an application that can treat the Multisim simulation measurements as data to acquire, similar to hardware.Below we see a completed LabVIEW application which utilizes the connection to automated simulation to benchmark prototype behavior.6/71. 2. 3. 4. 1. 2. 3. 4. 5. As you can see in the above figure, there are two sets of plots on each axis for gain and phase. In the magnitude plot the red simulated data, and white physical measurements are plotted on thegraph. Visually we can identify the difference between the sets of data.Since this was completely automated in a single application, there was no need to transfer files, or intermediate steps. Acquisition, analysis and presentation of both simulated and real data was alldone in one, completely integrated stage. Analyzing the ApplicationIn the attached file you will see the code (MixedSignalSimVsRealWorld.llb) to be able to:7829_compare_app.zipAcquire simulation data from Multisim (in an attache